Fix failure when get_meta_doc() is called

cloudinit/cmd/main.py

@@ -344,7 +344,7 @@ def _should_wait_via_user_data(
             version="24.4",
             requested_level=logging.WARNING,
             msg="Unexpected failure parsing userdata: %s",
-            args=e,
+            args=(e,),
         )
         return True, "failed to parse user data as yaml"
 

cloudinit/config/schema.py

@@ -1457,6 +1457,26 @@ def handle_schema_args(name, args):
         )
 
 
+def get_meta_doc(*_args, **_kwargs) -> str:
+    """Provide a stub for backwards compatibility.
+
+    This function is no longer used, but earlier versions of modules
+    required this function for documentation purposes. This is a stub so
+    that custom modules do not break on upgrade.
+    """
+    lifecycle.log_with_downgradable_level(
+        logger=LOG,
+        version="24.4",
+        requested_level=logging.WARNING,
+        msg=(
+            "The 'get_meta_doc()' function is deprecated and will be removed "
+            "in a future version of cloud-init."
+        ),
+        args=(),
+    )
+    return ""
+
+
 def main():
     """Tool to validate schema of a cloud-config file or print schema docs."""
     parser = get_parser()

cloudinit/lifecycle.py

@@ -128,7 +128,7 @@ def log_with_downgradable_level(
     version: str,
     requested_level: int,
     msg: str,
-    args,
+    args: tuple,
 ):
     """Log a message at the requested level, if that is acceptable.
 
@@ -145,9 +145,9 @@ def log_with_downgradable_level(
     :return: True if the message should be logged, else False.
     """
     if should_log_deprecation(version, features.DEPRECATION_INFO_BOUNDARY):
-        logger.log(requested_level, msg, args)
+        logger.log(requested_level, msg, *args)
     else:
-        logger.debug(msg, args)
+        logger.debug(msg, *args)
 
 
 def deprecate(

tests/unittests/cloudinit/test_lifecycle.py

@@ -0,0 +1,32 @@
+import logging
+
+import pytest
+
+from cloudinit import lifecycle
+
+LOG = logging.getLogger()
+
+
+class TestLogWithDowngradableLevel:
+    @pytest.mark.parametrize(
+        "version,expected",
+        [
+            ("9", logging.ERROR),
+            ("11", logging.DEBUG),
+        ],
+    )
+    def test_log_with_downgradable_level(
+        self, mocker, caplog, version, expected
+    ):
+        mocker.patch("cloudinit.features.DEPRECATION_INFO_BOUNDARY", "10")
+        lifecycle.log_with_downgradable_level(
+            logger=LOG,
+            version=version,
+            requested_level=logging.ERROR,
+            msg="look at me %s %s!",
+            args=("one", "two"),
+        )
+        records = caplog.record_tuples
+        assert len(records) == 1
+        assert records[0][1] == expected
+        assert records[0][2] == "look at me one two!"

tests/unittests/config/test_schema.py

@@ -27,6 +27,7 @@
     SchemaValidationError,
     annotated_cloudconfig_file,
     get_jsonschema_validator,
+    get_meta_doc,
     get_schema,
     get_schema_dir,
     handle_schema_args,
@@ -2278,3 +2279,14 @@ def test_handle_schema_args_unknown_header(
         assert read_cfg_paths.call_args_list == [
             mock.call(fetch_existing_datasource="trust")
         ]
+
+
+class TestDeprecation:
+    def test_get_meta_doc_deprecation(self, caplog):
+        """Test that calling get_meta_doc() emits deprecation.
+
+        Ensures that custom modules calling `get_meta_doc()` can still
+        function but receive deprecation warning.
+        """
+        get_meta_doc("some", "random", "arguments", plus="kwargs")
+        assert "The 'get_meta_doc()' function is deprecated" in caplog.text